1. The use of username@nexus
OUCS has always heavily discouraged username@machine for use as an email address, principally because it causes confusion and email address changes when services are replaced or renamed. That position will not change with the introduction of the Oxford Nexus groupware solution.
We recognize however some units have 'Direct Deliver' status for their email, i.e. where email is sent direct to the unit Mail Transport Agent (MTA) regardless of what is in front of the "@" symbol. These units have to use username@machine-type addresses to route users' mail to the right place, including to Herald and, in future, Nexus. This may be direct routing from the unit MTA or it may be from another machine within the unit.
For the above reason, Nexus will be able receive email sent to username@nexus but we intend to refer to such addresses as "routing addresses" rather than "email addresses" and ask you always to inform your users that their address is of the form firstname.lastname@example.org. This should avoid any future confusion or email address changes as the Nexus service develops end evolves.